Worth to note:
Do NOT use pywallet on your file
without backups.
The chance exists that the file won't be accessible / readable anymore after you run pywallet on it. There already were several cases.
Always have one (or multiple) backups of your wallet file before trying to use some tools to gain access to your private keys.
This only happens if you name the output file same as input, don't spread FUD. I have read the source code, pywallet does NOT tamper with
the original file.